Costa limped off with a hamstring injury in the second half of Chelsea’s 3-2 win at Hull on Sunday, sparking fears he may withdraw from international duty.
The Spanish federation (RFEF) said in a statement: “Costa will undergo tests on Monday in London and the results will be available to Spain’s medical staff for their evaluation.”
The Brazil-born forward missed games against Belarus and Germany because of a hamstring problem back in November.
Malaga striker Juanmi has been added to the group, meanwhile.
Juanmi, who has scored seven goals in 24 games for Malaga this season, has won the European Championship twice with Spain’s U19s but is yet to be capped at senior level.
A statement from RFEF read: “Malaga striker Juanmi has been called up this morning by national coach Vicente del Bosque for this month’s games against Ukraine and Holland.
“The Malaga striker will arrive tonight to Spain’s headquarters in Las Rozas(Madrid).”
Spain are without Valencia forward Paco Alcacer, who recently recovered from a knee injury but is not 100 per cent fit.
Del Bosque named Sevilla winger Vitolo, who has yet to play for Spain, and Juventus striker Alvaro Morata in the initial squad.
Spain host Ukraine in a Euro 2016 qualifier on March 27 before travelling to Holland for a friendly four days later.